Evolution and risk factors of anal incontinence during the first 6 years after first delivery: a prospective cohort study

Abstract

Objective: To explore changes in prevalence of anal incontinence (AI) from late first pregnancy to 6 years postpartum, and to evaluate possible risk factors for changes in AI during the 6-year period. Design: Prospective longitudinal cohort study. Setting: Two Norwegian health regions. Population or sample: Women with first deliveries between May 2009 and December 2010. Methods: Participants reported AI in late pregnancy, 6 months, 1 and 6 years after first delivery using postal or digital questionnaires. AI prevalence was calculated, and mixed effects Poisson regression analyses with robust variance were applied. Main outcome measures: AI from late pregnancy to 6 years postpartum. Results: Among 1571 participants, 65% had normal vaginal first deliveries, 20% had vaginal deliveries complicated by instrumental intervention and/or obstetric anal sphincter injury (IVD ± OASIS). Nearly 1 in 10 women reported persistent incontinence during the 6 years. The overall AI prevalence was reduced from late pregnancy to 1 year postpartum for all modes of delivery. At 6 years postpartum, women with IVD ± OASIS had a higher AI prevalence (23%; 95% CI 16–30%) compared with women with caesarean section (8%; 95% CI 2–13%) or normal vaginal delivery (12%; 95% CI 9–16%). Moreover, women who were <23 years, ≥34 years, unemployed during first pregnancy, who had active bowel disease (PR: 2.4; 95% CI 2.0–2.7), or bowel evacuation problems during the 6-year period had higher AI prevalence. Conclusions: Mode of first delivery modified AI prevalence during the 6-year period, whereas age, bowel disease and bowel evacuation problems were associated with higher prevalence of AI from late first pregnancy to 6 years postpartum. Tweetable abstract: Complicated vaginal delivery, age and bowel emptying problems increase the risk of long-term anal incontinence.